As compared to single phase DC-DC power converters, a multi-phase switching power converter such as a multi-phase buck converter offers improved efficiency for high current loads. In addition, multi-phase operation lowers the ripple current and output voltage ripple. To respond to load current changes, a multi-phase switching power converter may implement phase shedding such that different numbers of phases are activated depending upon the load current. Within each activated phase, a pulse-width modulator controls the duty cycle depending upon feedback from the output voltage. But the feedback-controlled (closed loop) control of the duty cycle is relatively slow and thus cannot accommodate rapid changes in the output current. Moreover the activation of additional phases can result in serious inter-loop current spike between the inductors of the existing phases and the inductors of the newly-added phases.
Accordingly, there is a need in the art for multi-phase switching power converters with improved response speeds.